Hot-air furnace



Nov. 7, 1950 F. l.. MEYER HOT-AIR FURNACE Filed July 14, 1947 3 Sheets-Sheet 1 me/who@ F. L. MEYER HOT-AIR FURNACE Nov. 7, 1950 3 Sheets-Sheet 2 Filed July 14, 1947 lll/lllIIIlII/IllllllllllllllIlllIlIIlIll/IllllIlIIlI/l 3 Sheets-Sheet 3 F. L. MEYER HOT-AIR FURNACE fr@ E Nov. 7, 1950 F'iled July 14, 1947 @IUE A a@ f Ill] .g Vx IIII.

Patented Nov. 7, 1950 UNITED STATES PATENT OFFICE HOT-AIR FURNACE Frank L. Meyer, Peoria, Ill.

Application July 14, 1947, Serial No. 760,830

'I'his invention pertains to improvements in furnaces of the warm air type.

The main object of the invention is to so construct a furnace that there shall be no leakage of gases from its combustion drum into the space created between said drum and the usual furnace casing to the end that such gases cannot reach the warm air conducting pipes.

Another object is that any gases escaping from the combustion drum, other than those passing away through the smoke pipe, will be delivered wholly outside the furnace rather than that they nd their way into said warm air pipes.

Still another object is to so construct the parts of a furnace that the wall of the combustion drum will have a direct and secure connection in a gas tight manner with the frame that supports and carries the fire door as contrasted with the old and well known insecure and unreliable methods involving packed joints, again to the end that gas leakage into the heat conducting pipes is obviated.

Heretofore, the throat member leading from the combustion drum, and through which fuel is introduced, has terminated at or near the door frame and mechanically secured thereat together with the introduction of packing material at the place of joining. As is Well known, no type of packing can be relied upon to provide a permanent non-leaking joint from the fact that in time the material shrinks and falls away and thus gas leakage results. By reason of such insecure methods the structure herein to be described, or its equivalent, is provided as a remedy, and upon which complete reliance may be placed.

In the appended drawings forming part hereof:

Figure 1 is a side elevation lof a portion of a furnace in part section showing portions of the invention in connection therewith.

Figure 2 illustrates in perspective,'and on a larger scale, part of a combustion drum of Figure l., as seen from its front.

Figure 3 is a horizontal section of part of the furnace of my invention taken on line 3-3 of Figures 1 and 2 but much enlarged. 1

A Figure 4 is an enlarged detail, in section, of parts shown in Figure 3.

Figure 5 is likewise an enlarged detail also of parts shown in Figures 3 and 4, and

` Fig. 6 is a perspective View of a furnace embodying the invention, a portion of the outer furnace 3 Claims. (Cl. 126-99) casing being broken away to show details of the construction.

The embodiment of the invention illustrated in Figs. l and 2 employs a cylindrical combustion drum l provided With a forwardly extending throat portion comprising a sloping top member 2, a pair of vertical side walls 6, and a vertical front panel 3. It is preferable that the sides and the front of the throat portion extend to the base of the furnace, so that the front 3 may be provided with both a fire door opening and an ash pit door opening.

The combustion chamber or drum I is posi-v tioned within and spaced from a main furnace casing 5, and the casing 5 is provided with a frontal opening defined by the hooked edges indicated at 5 in Figs. 3 and 4, this frontal opening being designed to accommodate the front 3 of the throat portion. It will be understoodthat the hooked edges 5 extend continuously along the sides of the front opening, and that the bottom of this opening is defined by the base of the furnace when the throat portion of the combustion drum extends for the full length of the drum. As illustrated in Figs. 3 and 4, the hooked edges 5 are spaced somewhat from the corresponding portions of the throat portion. It is necessary that any joints employed in fabrication of the combination drum and its throat portion be gas tight, so that gases from the combustion chamber cannot escape into the hot air space between the combustion drum and the furnace casing.

In the front portion 3 at an appropriate position the fire door opening fi is provided, at which is placed the door frame l of steel, this being of such dimensions in encircling the opening as to cover the margins of the metal at such opening while extending partially beyond said margins over said opening as clearly shown in the last four figures of the drawing.

The said frame is welded to the portions 3' and 6 at al1 the angles of joining, the welding being indicated at 8 in figures 4 and 5, providing a gas tight, unified structure, the door 4 being, of course, hinged 'to4 the frame in any usual manner. The abutting faces of door and frame may be surface ground to provide against gas leakage. In Welding the steel extensions 3 and 6 to the steel frame 'l Va permanent connection results due to joinin of like metals. f

Secured to front wall 3 of the throat portion of combustion chamber I along a continuous line closely encompassing door frame I is a packing retaining flange I8. A packing I6, preferably of asbestos rope, is held between flange I8 and the outer edge of door frame 'I.

To close that portion of the frontal opening of casing 5 not lled by door frame 1, I provide a front member 9. As will be seen in Fig. 4, the front member 9 is provided with an outer inturned edge I which engages with the hooked edge of the casing 5. The front member` 9 is also provided with an inturned ange I5 imbedded in the packing I6 adjacent to the outer edge of door frame 'I The front memberl 9 is shaped to conform to the frontal opening of casing 5 previously described, and thus in usual practice will be rectangular and is provided with an opening defined by the fiange I5 and aligned with the re door opening 6'.

Secured to the front member 9 in any suitable manner, as by welding, are angled frameV members I2 having spaced openings adapted to be engaged by a plurality of threaded studs I I on side walls 6, as shown in Fig. 3. When the frame members I2 are fixed in assembled position by application of the nuts I4, as will be seen from Fig. 3, the front member 9 is securely held with its inturned flange I5 firmly engaged with packing IB.

The combination of the door frame l, the continuous welds 8 securing the door frame to member. 3, the packing I t, and front member 9 provides an effective seal for the front opening in casing 5. rIhis structure prevents hot gases,

therefrom to provide an air heating space surrounding said drums, said drum having a forwardly extending throat portion terminating in a vertical front wall situated substantially in the plane of the frontal opening of said casing, the front wall of said throat portion being provided with a re door opening; a re door frame Secured to said front wall by a continuous peripheral Weld providing a gas-tight seal between said frame and said wall, said frame encompassing said fire door opening; a packing secured to said front wall adjacent said door frame outside thereof and eX- tending continuously aroundsaid frame, and a frontal closure member 'for the space between said fire door frame and the edges of said casing dening said frontal opening, said closure member being secured to said casing and including a continuous inturned ange held in rm engagement with said packing to form a gas-tight seal completely around said fire door frame, whereby hot gases escaping outwardly through said door frame when the door is opened are prevented from being drawn around said door frame into said air heating space.

2. In a hot air furnace, an outer furnace casing provided with a frontal opening; a combustion drum situated within said casing and being spaced therefrom to provide an air heating space around said drum, said drum being provided with a forwardly extending throat portion including vertical sidewalls and a vertical front wall, the front wall of said throat portion being situated substantially in the plane of the frontal opening of which often pass outwardly through the fire door opening when the door is opened, from being Az drawn into the heating space.

Itis to be understood that while the structure comprising the member 9 and associated parts has been described as a convenient means for the several purposes named other means may be emp-loyed to answer the end sought. It has long been the desire to in some manner prevent leakage of gases from the heating unit or combustion drum into the space enclosed by the casing 5. construction has been found to answer that desire in', that any such leakage is necessarily outside the furnace casing 5 rather than within it.

It is clear that since the permanent tight connection between the extension 2, 3, E and the door frame, instead of a cemented joint of the old type with its faults mentioned earlier herein, is

wholly advantageous.

While the welding operation is all that could be desired any other means that will provide a permanent seal of equally sturdy nature may, perhaps; be available.

The combustion drum, it is seen, retains its usuallposition with respect to the casing 5, yet its extension effectually bridges the enclosed circular space within the casing without materially reducing the overall capacity of said space.

Since the frame I8 is attached to the main furnace structure in the factory the asbestos rope lling I6 may likewise be applied and the front 9 can be applied readily on location making a wholly complete leak proof installation without requiring cementing operations on such location, thereafter merely attaching the casing 5 by hooking its edges`5 in place on the hooks IG of the parts 9 islall 'that is required.

I claim:

I. In a hot air furnace, an outer furnace casing provided with a frontal opening; a combustion drum situated within said casing and spaced The present or equivalent manner of 'A said casing and being provided with a re door opening; a fire door frame secured'to said front wall by a continuous peripheral weld effecting a gas tight seal between said frame and said front wall, said frame encompassing said re door opening; a packing secured to said front wall adjacent said door frame outside thereof and extending continuously around said frame; a vertical fr-ame member removably'attached to each ofthe side walls of the throat portion of said combustion drum, and a frontal closure member for the space between said fire door frame and the edges of said casing defining said frontal opening, said closure member being permanently attached to said vertical frame members and including an opening to accommodate said fire door frame, said openingbeing defined by a continuous inturned flange held in firm engagement with said packing to provide a gas-tight seal completely around said fire door frame.

3. vIn a hot air furnace, an outer casing including a frontal opening; a combustion drum situated within said casing and spaced therefrom to provide an air heating space around said drum, said combustion drum including a forwardly eX- tencling throat portion having vertical side walls and a vertical front wall, the vertical front wall of said throat portion being located substantially in the plane of the frontal opening of said casing and being provided with a re door opening; a re door frame permanently secured to said front wall about said fire door opening by a continuous peripheral weld effecting a gas-tight seal between said front wall and said frame; a packing secured to said front wall adjacent to andextending completely around said fire door frame on the outside thereof;` a frontal closure panel for the space between said fire door frame and the edges of said casing defining said frontal opening, said panel including an opening to accommodate said fire door frame defined by an inturning flange adapted to be engaged with the entire length of aszafioe 6 REFERENCES CITED The following references are of record in thev file of this patentiVv UNITED STATES PATENTS 5 Number Name Date 970,117 St. John Sept. 13, 1910 1,543,112 Laube June 23, 1925 1,620,805 Dawson Mar. 15, 1927 1,692,576 Rote Nov. 20, 1928 1,751,829 McNaney Mar. 25, 1930 1,916,644 Suppes July 4, 1933 

